Trivia

On the day of the special's UK theatrical release, Sir John Hurt was knighted for his services to drama by Queen Elizabeth II at Windsor Castle.

This special won Evcom Screen Awards Gold Award for Music.

The special aired on Virgin Atlantic flights out of London from 1st - 8th August.

This special takes place between the nineteenth and twentieth seasons. However, there are some hints with voice actors and changes that this was produced before the nineteenth season in 2014, these being:

Stanley not having a lamp, lamp-iron, brake-pipe or brake-pipe outlets all of which he received in the nineteenth season.

Keith Wickham voicing Percy in the UK dub.

Tidmouth Sheds still lacking the buffers that appeared behind each berth partway through the nineteenth season.

From this special until Big World! Big Adventures!, every new special is produced before the season that takes place before it. Because of this, it results in several continuity errors that are the result of animation, voice acting or staff members.

This special marks the first of multiple things:

The first appearances of the Arlesdale Railway and the Thin Clergyman in the television series. The Awdry family was consulted for rendering the latter for the special.

The first full-length CGI special not to feature a stylised opening sequence, excluding The Adventure Begins.

The first special in which engines sing an original song.

The first time in the television series that The Mainland is explicitly shown to be England.

The first time all engines numbered 1 to 11 have appeared and spoken in full CGI.

The first time The Pack is seen interacting with engines other than Thomas and Percy.

The first special where Rob Rackstraw voices Toby in the UK and Christopher Ragland voices Percy in the US.

Toby, Diesel, Victor, Jack and Captain's first appearances in a special since King of the Railway.

The first time characters who have the same name appear at the same time.

Duck, Oliver and Daisy's first speaking roles in a special.

Donald, Douglas, Samson and Toad's first appearances in a special.

Nathan Clarke and Jamie Campbell Bower join the voice cast and Eddie Redmayne and John Hurt make special guest voice appearances.

This special marks the one-time of a few things:

The only production to feature Eddie Redmayne as part of the voice cast to date. As a result, Steven Kynman took over Redmayne's role of Ryan from the twentieth season onwards. It is also the only production to feature John Hurt as part of the voice cast prior to his death.

The first and only appearance of Sailor John until Big World! Big Adventures! and his only speaking role to date.

The first and only special to date in which Percy only has one line. He is also one of the few characters in the special to have one line, with the others being Emily who exclaims "Thomas!" when he is shunting Gordon's express coaches through the junction, Bill and Ben during the scene at Brendam Docks and Daisy towards the end.

Drafts of the film's script were shown in the YouTube video, 70 Years of Friendship. According to these drafts:

"The Great Treasure Hunt" and "Legend of the Lost Treasure" were both working titles for this special.

The special was to open with Thomas passing the original windmill. The final film instead features the windmill from the fifth season onwards, possibly due to time constraints.

A rendition of the original opening theme was considered for the special. However, this idea ultimately did not materialise in the final film.

Thomas' coaches remind him that the passengers do not like being bounced like peas in a pod, as Andrew Brenner had misquoted the line during an interview with SiF. The line is correctly quoted ("...bounced about like peas in a frying pan") in the final special.

Some parts of the special were cut out of the PBS broadcast due to time constraints:

The engines trying to wake up Thomas.

Marion talking to Alfie and Oliver while they were digging.

A few scenes of the engines on the new branch line was cut along with the song.

On the week of its DVD release in the UK, Ben Dowell gave the special a four-star rating and branded it as the DVD of the week in the Radio Times.

A few references were made throughout the special:

The opening pays homage to the original television series opening, with Thomas passing a windmill, going under a bridge and eventually pulling into Ffarquhar station.

Clarabel tells Thomas that his passengers do not like being bounced like peas in a frying pan. This is a reference to the first season episode Thomas and Bertie.

Marion believing that the small engines were magical is similar to what James and Henry thought they were in Ballast from the Railway Series book Small Railway Engines.

The way the other engines wake up Thomas is similar to the first season episode Thomas and Gordon, primarily its retelling in The Adventure Begins and just like The Adventure Begins, Henry tells Thomas that Gordon is waiting for his coaches.

The Fat Controller saying to Thomas that he does not want to hear his excuses could be a reference to the nineteenth season episode Who's Geoffrey?

The second time Skiff tells Sailor John that they need to leave, the former sings part of the Banana Boat Song.

In Never Overlook A Little Engine, there is a cake with "70TH" written on it; this is a reference to the 70th anniversary of the first Railway Series books.

Duck saying that it feels like Donald and Douglas have been gone for ages is likely a reference to the fact that, when the special was released, the twins had been completely absent from the television series for seven years.

Just after the scene where Ryan pulls over the pirate ship, in the shot of the boats in the harbour, Toby's bell from the second and third season can be heard faintly in the background. This is presumably meant to be the sound of a distant bell buoy.

The Chinese theatrical release of this special also includes an edited version of the YouTube documentary 70 Years of Friendship, dubbed into Mandarin.

This is the fourth known special to be dubbed into Hebrew.

In both narrations, as Thomas approaches the construction site after his visit with Bert, Rex and Mike, he is humming Never Overlook a Little Engine.

In the trailer when Sailor John watches Donald and Douglas bring the Pirate Ship to Arlesburgh Harbour, the sunlight was shown behind the lighthouse, but in the special itself, the sunlight is shown in the distance beside the town.

On 1st June 2018, the songs from this special were released on iTunes, Spotify and other music streaming services.

The special aired on Nick Jr. split into three half hour blocks on 23rd - 25th July 2018 by Mattel Creations. Also, because the nineteenth season opening was used, the credits that were used in the opening of the special were removed. Treehouse TV also airs the three-part version of the special.

Goofs

When Thomas is about to run into Toby and is switched onto the passing siding, Henrietta can be seen behind Toby. However, when Thomas is seen returning onto the branch line, Henrietta is missing.

The digital release is slowed down to 24fps, which causes audio distortion.

Annie's wheels are already moving before Thomas starts when they leave Ffarquhar.

A hand can be seen through Percy's cab when he leaves Tidmouth Sheds. The same thing happens to Thomas in the first scene of "Never Overlook a Little Engine."

When Emily brakes at Knapford, her bogie wheels spark, but these wheels are not fitted with brakes. Ryan's trailing wheels also briefly spark when he tries to stop the pirate ship.

When Marion first sees Mike, his side rods are black.

When Donald passes Marion at Arlesburgh Junction, the rivets on his smokebox are red.

When Duck meets Donald and Douglas, he shunts some trucks and reverses slightly before greeting them. But at the end of the scene when the twins leave, the trucks have disappeared.

Just before Thomas runs the red signal when he is chasing Sailor John and Skiff, he is on the right-hand track (from his perspective). But after passing through the tunnel, he is on the left-hand track for the remainder of the chase.

Rex is missing his leading bogey for most of the special. His trailing bogey also disappears in one shot, as does Mike's leading bogey in a different shot when they tour Arlesburgh.

Just before "Never Overlook a Little Engine" begins, Thomas' trucks disappear. Just after the song ends, the trucks have reappeared, but have moved further away.

Just before the singing begins in "Never Overlook a Little Engine," Mike's mouth does not move when he says, "Oh".

During "Never Overlook a Little Engine", when the Small Engines' drivers' hats blow away, Rex's driver's hat disappears for a split second.

As the camera zooms out while the crew lays track, Douglas pulls into the shot, but Oliver's whistle is heard. Then, when Oliver pulls up and says "Here we are!" Douglas' whistle is heard.

When Thomas arrives at the ballast hopper after taking on the bad coal, his trucks are already filled with ballast.

When the narrator says "Marion was working on the next cutting," Jack moves without his wheels turning.

When Thomas shunts the dynamite into the cavern, the trucks are still on the rails, but when the Fat Controller speaks from the hill and a shot of him looking down at Thomas is shown, the trucks have disappeared.

When Marion is asking Thomas to guess what is in her shovel as he passes by, he is lower to the ground than usual, with his wheels clipping through the rails and ground.

When Thomas stands up to Sailor John and shunts Skiff out of his way, his trucks are red. In a close-up, however, one turns green. In the next shot, they are all red again.

When Thomas warns Ryan about the rope on the pirate ship during the chase scene, his paintwork is no longer scratched and dirty.

When Thomas passes Gordon during the chase, the points are set to allow him to follow Sailor John, but they are never set back for Gordon, who passes over them moments later.

Steam emits from Thomas' whistle when Gordon's whistle is heard during the chase.

When the Small Railway Engines push the ballast trucks off the chute, the buffers on the chute's track disappear.

When Sailor John drops Skiff's oar in the water, it does not make a splash.

After Thomas says "It's good to be back, Annie," Clarabel has Annie's voice. In the same shot, Clarabel keeps laughing even when her mouth stops moving.

When Thomas asks about Daisy at the opening of the branch line, Annie and Clarabel disappear.

In the end credits, Gordon is missing his tender wheels.

Christopher Ragland is credited in the UK credits despite none of his characters speaking in that dub.

During his scenes at Arlesburgh Junction, Oliver's eighteenth season model is used. During the grand opening of the new branch line, his nineteenth season model is used.

When Thomas pushes Skiff into the siding and Sailor John falls backwards, his hand clips through Skiff's sail.

When Thomas arrives at Knapford to collect Gordon's coaches, Annie and Clarabel have their voices switched.

When Ryan first arrives, Diesel can be seen in the background with some trucks. However, in a close-up of Thomas, the trucks disappear.

During the branch line's ceremony, Donald is placed behind Marion. But when the engines leave for the harbour, Donald moves forward as if Marion is not there. A few shots later, he has switched to the same track as Douglas.

After "Never Overlook a Little Engine," Rex is on the track right next to Thomas and is pulling some wool trucks, but two shots later, he is on a different track and pulling some ballast trucks.

At the end of the special in the Brendam Docks scene, Salty is set back into his trucks, clipping through the one immediately behind him.

When Donald comes round the bend before the unstable track, his train has no brake van, but in a close-up shot, his train gains one. Also before he rounds the bend, he has the number 10 on his tender, Douglas' number.

When Thomas leaves to take his trucks to the dump, Ryan passes him and whistles, but no steam emits from his whistle.

There are several mistakes in the German dub:

Duck is called an American locomotive.

Branch lines are called "Streckenabschnitte" (track sections).

When Annie says "What new branch line?" she has Clarabel's voice.

When Rex sings "Like Me!" he has Thomas' voice.

When Ryan first arrives, it is said that he is supposed to work on the new branch line, but he is sent to Thomas' branch line.

When Ryan collects Annie and Clarabel, the two coaches switch places from where they were earlier on.

On the DVD cover and cinema posters, Ryan's smokebox saddle is purple, instead of black.

When Thomas goes past the ship on display at Arlesburgh Harbour, the red lining on the back of his coal bunker is missing.

When the small engines turn into butterflies in "Never Overlook a Little Engine," Mike and Rex's liveries have been switched.

When Thomas is rescued from the water towards the end, Ryan's cab is not rendered properly, as the buildings in the background can be seen through his cab windows.